Band-pass filtering circuit, control method thereof and MEMS gyroscope drive circuit

Abstract

The invention discloses a band-pass filtering circuit and a control method of the band-pass filtering circuit. The band-pass filtering circuit receives input signals and provides effective in-band output signals with out-of-band noise being filtered out. The band-pass filtering circuit sequentially executes the following steps in each sampling cycle that the input signals are sampled at the input end of an operational amplifier and stored in a capacitor at the input end in an electric charge mode, sampling causes changes of the quantity of electric charge of the capacitor at the input end, and the part of electric charge, changed due to sampling, of the capacitor at the input end is transmitted to an output capacitor from the input end of the operational amplifier; part of capacitance is reset to a common mode voltage, and the remaining capacitance maintains the quantity of electric charge in the last state. A switched capacitor circuit technology is adopted by the band-pass filtering circuit, the structure is simple, only one operational amplifier is needed, the area is small, the complexity is lowered, in this way, the power consumption of a whole chip is lowered, and the area of the chip is reduced.

Description

technical field [0001] The invention belongs to signal processing technology, and in particular relates to a band-pass filter circuit, a control method thereof, and a MEMS gyroscope driving circuit. Background technique [0002] The application fields of Microelectromechanical Systems (MEMS for short) are becoming more and more extensive. In these applications, MEMS gyroscopes are an important angular velocity sensor. [0003] A MEMS gyroscope generally includes a mass block, and driving comb-teeth electrodes and drive-detection comb-teeth electrodes respectively arranged on the mass block along first and second directions perpendicular to each other. The comb-teeth electrodes are driven to apply an electrostatic force to the mass block along the first direction, so that the mass block resonates along the first direction. When there is an angular velocity in the motion of the system, the mass block will vibrate along the second direction due to the force in the second dire...

AI Technical Summary

Problems solved by technology

However, existing bandpass filters use two or more op amps, resulting in large circuit area, high power consumption, and high cost, which cannot meet the needs of portable products

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